U.S. Pat. Nos. 5,532,415, 5,387,612, 5,453,446, 5,457,133, 5,599,991, 5,744,500, 5,891,923, 5,668,181, 5,576,353, 5,519,061, 5,786,390, 6,316,504, 6,630,514, 7,750,051, and 7,855,233 disclose R(+)-N-propargyl-l-aminoindan (“R-PAI”), also known as rasagiline, and its pharmaceutically acceptable salts. These U.S. patents also disclose that rasagiline is a selective inhibitor of the B-form of the enzyme monoamine oxidase (“MAO-B”) and is useful in treating Parkinson's disease and various other conditions by inhibition of MAO-B in the brain.
U.S. Pat. Nos. 6,126,968, 7,572,834, and 7,598,420, U.S. patent application Ser. Nos. 12/283,022, and 12/283,107 and PCT publications WO 95/11016 and WO 2006/014973, hereby incorporated by reference, disclose pharmaceutical compositions comprising rasagiline and processes for their preparation.
AZILECT® is a commercially available rasagiline mesylate immediate release formulation indicated for the treatment of the signs and symptoms of idiopathic Parkinson's disease as initial monotherapy and as adjunct therapy to levodopa. The current marketed formulation of rasagiline (Azilect®) is rapidly absorbed, reaching peak plasma concentration (tmax) in approximately 1 hour. The absolute bioavailability of rasagiline is about 36%. (AZILECT® Product Label, May 2006).
A concern in using monoamine oxidase (“MAO”) inhibitors is the risk of hypertensive crises, often called the “cheese effect.” (Simpson, G. M. and White K. “Tyramine studies and the safety of MAOI drugs.” J Clin Psychiatry. 1984 July; 45 (7 pt 2): 59-91.) This effect is caused by inhibition of peripheral MAO. A high concentration of peripheral MAO is found in the stomach.
Rasagiline is a nonspecific inhibitor of MAOA, and has been shown to inhibit MAOA activity in the brain and liver of rats. Youdim M, Gross A, Finberg J, “Rasagiline [N-propargyl-1R(+)-aminoindan], a selective and potent inhibitor of mitochondrial monoamine oxidase B”, Br. J. Pharm. 132:500-506 (2001).